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Proportional Integral Controller Enhanced (PIE): A Lightweight Control Scheme to Address the Bufferbloat Problem (RFC8033) Disclosure Number: IPCOM000249483D
Original Publication Date: 2017-Feb-01
Included in the Prior Art Database: 2017-Mar-01
Document File: 60 page(s) / 59K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

R. Pan: AUTHOR [+4]


The explosion of smart phones, tablets, and video traffic in the Internet brings about a unique set of challenges for congestion control. To avoid packet drops, many service providers or data-center operators require vendors to put in as much buffer as possible. Because of the rapid decrease in memory chip prices, these requests are easily accommodated to keep customers happy. While this solution succeeds in assuring low packet loss and high TCP throughput, it suffers from a major downside. TCP continuously increases its sending rate and causes network buffers to fill up. TCP cuts its rate only when it receives a packet drop or mark that is interpreted as a congestion signal. However, drops and marks usually occur when network buffers are full or almost full. As a result, excess buffers, initially designed to avoid packet drops, would lead to highly elevated queuing latency and latency variation. Designing a queue management scheme is a delicate balancing act: it not only should allow short-term bursts to smoothly pass but also should control the average latency in the presence of long-running greedy flows.

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Internet Engineering Task Force (IETF)                            R. Pan Request for Comments: 8033                                  P. Natarajan Category: Experimental                                     Cisco Systems ISSN: 2070-1721                                                 F. Baker                                                             Unaffiliated                                                                 G. White                                                                CableLabs                                                            February 2017

             Proportional Integral Controller Enhanced (PIE):     A Lightweight Control Scheme to Address the Bufferbloat Problem


   Bufferbloat is a phenomenon in which excess buffers in the network    cause high latency and latency variation.  As more and more    interactive applications (e.g., voice over IP, real-time video    streaming, and financial transactions) run in the Internet, high    latency and latency variation degrade application performance.  There    is a pressing need to design intelligent queue management schemes    that can control latency and latency variation, and hence provide    desirable quality of service to users.

   This document presents a lightweight active queue management design    called "PIE" (Proportional Integral controller Enhanced) that can    effectively control the average queuing latency to a target value.    Simulation results, theoretical analysis, and Linux testbed results    have shown that PIE can ensure low latency and achieve high link    utilization under various congestion situations.  The design does not    require per-packet timestamps, so it incurs very little overhead and    is simple enough to implement in both hardware and software.

Pan, et al.                   Experimental                      [Page 1]
 RFC 8033                           PIE                     February 2017

 Status of This Memo

   This document is not an Internet Standards Track specification; it is    published for examination, experimental implementation, and    evaluation.

   This document defines an Experimental Protocol for the Internet    community.  This document is a product of the Internet Engineering    Task Force (IETF).  It represents the consensus of the IETF    community.  It has received public review and has been approved for    publication by the Internet Enginee...